Like a balanced diet and an exercise routine, sleep is a critical component of a healthy lifestyle. Too little sleep can do much more than simply ruin your day by leaving you feeling groggy, cranky and distracted. Sleeping less than seven hours a night — also known as short sleep — can pose serious health risks to you, and in some cases, those around you.

At least 50 million Americans suffer from sleep disorders or don’t get adequate sleep, according to the National Heart, Lung and Blood Institute. About 29 percent of Americans also sleep fewer than seven hours a night. Take a look at how a lack of shut-eye can boost these common health risk factors.

Cardiovascular

When you get too little sleep, you may be compromising your heart health. The risk is greater for those with a common cluster of factors that includes heart disease and diabetes.

Heart rate and blood pressure increase with sleep deprivation, according to recent research in Germany. Poor sleep also may be linked to irregular heartbeat conditions such as arrhythmia and atrial fibrillation (A-Fib), according to preliminary research presented at the American Heart Association’s Scientific Sessions 2016. Americans diagnosed with insomnia had a 29 percent higher risk of developing A-Fib, which can lead to heart failure or stroke. Researchers also found that those who frequently woke up at night had a 26 percent higher risk of developing A-Fib compared to their sounder-sleeping counterparts.

Stroke

Sleep deprivation also is associated with heightened stroke risk. Research shows that resting and sleep have a positive effect on blood pressure.

“When you rest, your body has the opportunity to reset, allowing your vital organs to do less work and for your blood pressure to lower,” says Jennifer Jones, BSN, RN, CNRN, at Orlando Health. “Researchers found that people who regularly got seven to eight hours of sleep, along with 30 to 60 minutes of vigorous exercise up to six times a week, had the lowest stroke risk.”

Mood Disorders

When you feel irritable following a sleep-deprived night, it’s not your imagination. Researchers at Harvard Medical School have connected chronic sleep loss with long-term mood disorders including anxiety, depression and mental distress.

Studies showed that participants who got four to four and a half hours of sleep per night reported heightened stress levels, as well as increased feelings of sadness, anger and mental fatigue.

Weight

A good night’s sleep may be a key to maintaining a healthy weight for both children and adults. Researchers have linked short sleep (getting less than seven to eight hours for adults) with weight-management challenges. Dozens of studies have explored the link between sleep duration and childhood obesity. Most have found a strong association between too little sleep and increased weight.

One of the largest and longest studies on adult sleep habits and weight, conducted at Harvard University, found that women who slept five hours or less were 15 percent more likely to become obese than those who slept seven hours a night. But, how are sleep and healthy weight management linked? It may be hormonal.

Someone who is sleep-deprived “may have higher levels of ghrelin, the hunger-inducing hormone, and less of leptin, the hormone that tells us we are full,” explains Lisa Cooper, a registered dietitian at Orlando Health. These hunger hormones may play a significant role in late-night snacking and associated weight gain.

“Sheer willpower will not keep you away from those cheese puffs at 10:00 pm if your hormones are working against you,” Cooper says.

Drowsy Driving

How often do we drive feeling a little tired? Driving while tired may seem harmless, but sleep deprivation can seriously increase accident risks for you and everyone sharing the road.

If you drive after only four to five hours of sleep, your performance can be “the equivalent to driving drunk,” says Dr. Chad Smith, a general and trauma surgeon at Orlando Regional Medical Center.

The National Sleep Foundation reports that driving after being awake 18 hours is comparable to driving with a blood alcohol level of .05 (.08 is considered legally intoxicated in the U.S.). If you drive after being awake for 24 hours, your impairment will be comparable to having a .10 blood alcohol level.

“Most people have probably driven while tired and may not see this as risky behavior on the same level as driving after consuming a few drinks,” says Dr. Smith. “But lack of sleep can have dangerous effects behind the wheel because it slows your reaction time, increases inattention and reduces response accuracy, which basically means your judgment and your ability to physically respond in a particular situation are impaired.”